1. Technical Field
The invention relates to protective caps and in particular to a construction and method for encasing fastener heads. More particularly, the invention relates to such a construction and method in which the cap is naturally adhesive, is moldable for encasing fastener heads of varying shapes and sizes, and is manufactured in a form which is easily stored and manipulated during installation.
2. Background Information
Fasteners such as bolts are used for innumerable fastening applications, including many outdoor applications or other applications where the fasteners are exposed to moisture. For example, bolts are commonly used for fastening metal roofing to the frame of commercial and industrial buildings, with the bolt heads typically being exposed to the outdoor environment. If the bolts are installed unprotected, moisture such as precipitation can seep through the bolt-receiving openings formed in the metal roof and into the interior of the building.
Various devices have been developed over the years for encasing fastener heads and/or sealing fastener-receiving openings. U.S. Pat. Nos. 3,134,290; 2,692,495 and 4,316,690 disclose molded plastic fastener heads. U.S. Pat. Nos. 2,688,497; 2,697,873; 2,927,495; 3,009,722 and 3,218,906 disclose various types of gaskets and the like for sealing fastener-receiving openings. U.S. Pat. Nos. 4,389,826 and 4,649,686 disclose protective coverings for fastener heads. U.S. Pat. Nos. 3,548,704; 3,885,492 and 4,582,462 disclose snap-fitted protective caps for fasteners.
The closest known prior art to our improved protective cap and method is shown in U.S. Pat. Nos. 2,710,113; 3,470,787 and 4,143,454. Patent No. 2,710,113 discloses pliable rubber protective caps for fasteners which are placed in position over a fastener, and which require a separate external sealer, as well as a separate internal sealer for filling the void within the cap adjacent to the fastener. In contrast, our improved protective cap is self-adhesive and does not require separate sealers, and is moldable about the fastener to eliminate the need for internal sealers. Patent No. 3,470,787 also discloses a protective cap for fasteners which is dome-shaped and is filled with a separate sealing material such as silicone rubber. Patent No. 4,143,454 discloses yet another protective cap which utilizes a separate sealing material.
Heretofore, another common sealing device and method for protecting fastener bolt heads, especially of the type used on metal roofs, was by manually applying a caulking or sealing compound about each individual bolt head. Such procedure is extremely time consuming and expensive.
Therefore, the need exists for a protective cap construction and method in which the cap effectively seals fastener heads of varying shapes and sizes without requiring separate adhesives, and which can be conveniently stored and handled in the field.